INFO: task syz.1.550:8057 blocked for more than 143 seconds. Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.550 state:D stack:29048 pid:8057 tgid:8048 ppid:5833 task_flags:0x400040 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:746 blk_trace_remove kernel/trace/blktrace.c:406 [inline] blk_trace_ioctl+0x23a/0x280 kernel/trace/blktrace.c:745 blkdev_common_ioctl+0x1665/0x2250 block/ioctl.c:623 blkdev_ioctl+0x1cb/0x6d0 block/ioctl.c:692 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efdcef8e169 RSP: 002b:00007efdcfe61038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007efdcf1b6160 RCX: 00007efdcef8e169 RDX: 0000000000000000 RSI: 0000000000001276 RDI: 0000000000000004 RBP: 00007efdcf010a68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007efdcf1b6160 R15: 00007ffcac921ec8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764 2 locks held by getty/5578: #0: ffff888036b510a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 2 locks held by syz-executor/5822: #0: ffff888079b100e0 (&type->s_umount_key#76){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888079b100e0 (&type->s_umount_key#76){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888079b100e0 (&type->s_umount_key#76){+.+.}-{4:4}, at: deactivate_super fs/super.c:505 [inline] #0: ffff888079b100e0 (&type->s_umount_key#76){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:502 #1: ffffffff8e3ccaf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 3 locks held by syz.1.550/8056: 1 lock held by syz.1.550/8057: #0: ffff888025dfa658 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_remove kernel/trace/blktrace.c:406 [inline] #0: ffff888025dfa658 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_ioctl+0x23a/0x280 kernel/trace/blktrace.c:745 2 locks held by syz.3.572/8127: #0: ffff888025dfcd58 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0xd7/0x1b0 kernel/trace/blktrace.c:631 #1: ffffffff8e43ed68 (relay_channels_mutex){+.+.}-{4:4}, at: relay_open+0x395/0xad0 kernel/relay.c:514 1 lock held by syz.3.572/8148: #0: ffff888025dfcd58 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_remove kernel/trace/blktrace.c:406 [inline] #0: ffff888025dfcd58 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_ioctl+0x23a/0x280 kernel/trace/blktrace.c:745 2 locks held by syz.6.997/9822: #0: ffffffff9012caa8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff9012caa8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390 #1: ffffffff8e3ccaf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x280/0x3c0 kernel/rcu/tree_exp.h:304 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:437 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 8056 Comm: syz.1.550 Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x60/0xc0 kernel/rcu/tree.c:736 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 75 5c 48 03 1c ed 00 bd cf 8d 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 0f b6 14 02 <48> 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 24 8b 03 c1 e8 02 RSP: 0018:ffffc9001cc3f780 EFLAGS: 00000a06 RAX: dffffc0000000000 RBX: ffff8880b8532de8 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff8bf46480 RDI: ffffffff8dcfbd08 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 00000000000137ed R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007efdcfe826c0(0000) GS:ffff888124ab0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f73d7b7fab8 CR3: 00000000351ce000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x2cd/0x350 kernel/locking/lockdep.c:5829 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2680 relay_destroy_buf+0x11f/0x3e0 kernel/relay.c:201 relay_remove_buf kernel/relay.c:221 [inline] kref_put include/linux/kref.h:65 [inline] relay_close_buf+0x144/0x1a0 kernel/relay.c:429 relay_open+0x765/0xad0 kernel/relay.c:529 do_blk_trace_setup+0x503/0xb50 kernel/trace/blktrace.c:590 blk_trace_setup+0xed/0x1b0 kernel/trace/blktrace.c:632 blk_trace_ioctl+0x146/0x280 kernel/trace/blktrace.c:730 blkdev_ioctl+0x108/0x6d0 block/ioctl.c:687 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efdcef8e169 Code: Unable to access opcode bytes at 0x7efdcef8e13f. RSP: 002b:00007efdcfe82038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007efdcf1b6080 RCX: 00007efdcef8e169 RDX: 0000200000000480 RSI: 00000000c0481273 RDI: 0000000000000004 RBP: 00007efdcf010a68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007efdcf1b6080 R15: 00007ffcac921ec8